Over 170 million people worldwide are infected with hepatitis C virus (HCV). Acute infection is usually silent, but the majority of infected individuals develop persistent infections (Major et al., 2001, “Hepatitis C viruses,” Fields Virology, 1127-1162; incorporated herein by reference). A small percentage of acute infections however resolve viremia with disease resolution. Cellular immunity is necessary, as a robust and sustained CD4+ T cell response is temporally associated with virus clearance leading to disease resolution (reviewed in Shoukry et al., 2004, Annu. Rev. Microbiol., 58:391; incorporated herein by reference).
Antiviral drugs (e.g., interferon or PEGylated interferon) taken alone or in combination with ribavirin (i.e., nucleoside analog which interferes with viral genome replication) can be used for the treatment of persons with chronic hepatitis C, but the cost of treatment is very high. Treatment with interferon alone is effective in about 10% to 20% of patients, while interferon combined with ribavirin is effective in about 30% to 50% of patients.
The present invention encompasses the recognition that antibodies may be developed that can be useful for prophylaxis, treatment, and/or diagnosis of HCV. A significant challenge for antibody-based vaccine development is defining conserved protective epitopes and generating antibodies that specifically recognize these epitopes.